Apparatus for harvesting mollusks

ABSTRACT

AN APPARATUS FOR HARVESTING MOLLUSKS OR THE LIKE COMPRISING A DREDGE FOR GATHERING SAID MOLLUSKS, A TUBE REFINING A PATH OF TRAVEL FOR SAID MOLLUSKS OPEN AT ONE END ADJACENT AND, SECURED TO SAID DREDGE, A GAS SUPPLY FOR DIRECTING GAS UNDER PRESSURE INTO SAID TUBE ADJACENT THE DREDGE TO INDUCE MOVEMENT OF THE MOLLUSKS THEREINTO, EQUIPMENT FOR MEASURING THE PRESSURE DIFFERENTIAL BETWEEN THE GAS IN SAID TUBE AND THE AMBIENT PRESSURE SURROUNDING THE DREDGE, AND EQUIPMENT OPERATIVELY ASSOCIATED WITH THE GAS SUPPLY AND MEASURING EQUIPMENT TO CONTROL THE SUPPLY OF GAS IN ORDER TO MAINTAIN A PREDETERMINED PRESSURE DIFFERENTIAL.

Dec. 7, 1971 M. H. DOYLE 3,624,932

APPARATUS FOR HARVESTING MOLLUSKS Filed April 6, 1970 Q Sheets-Sheet lFIG.1

INVENTQR HILTON H .DOY LE Dec. 7, 1971 M. H. DOYLE APPARATUS FORHARVESTING MOLLUSKS 2 Shouts-Shunt 2 Filed April 6, 1970 FIG.?)

INVENTOR MILTON ll. DOYLE United States Patent Office 3,624,932 PatentedDec. 7, 1971 3,624,932 APPARATUS FOR HARVESTING MOLLUSKS Milton H.Doyle, Ardsley, N.Y., assignor to Borden Inc., New York, N.Y.Continuation-impart of application Ser. No. 680,705, Nov. 6, 1967. Thisapplication Apr. 6, 1970, Ser.

Int. Cl. A01m 25/00 US. CI. 37-55 6 Claims ABSTRACT OF THE DISCLOSURE Anapparatus for harvesting mollusks or the like comprising a dredge forgathering said mollusks; a tube refining a path of travel for saidmollusks open at one end adjacent and, secured to said dredge; a gassupply for directing gas under pressure into said tube adjacent thedredge to induce movement of the mollusks thereinto; equipment formeasuring the pressure differential between the gas in said tube and theambient pressure surrounding the dredge, and equipment operativelyassociated with the gas supply and measuring equipment to control thesupply of gas in order to maintain a predetermined pressuredifferential.

This application is a continuation-in-part of co-pending applicationSer. No. 680,705, filed Nov. 6, 1967 and now abandoned.

BACKGROUND OF THE INVENTION Heretofore, various apparatus have been usedto harvest mollusks or the like from the ocean floors and beds atvarying depths. These apparatus have generally provided a tube or othermeans which is connected to a dredge dragged along the ocean floor forcarrying the collected mollusks, shellfish, claims, sponges, scallops,etc. to the boat towing the dredge. Generally, the movement of mollusksthrough the tube member is effected by supplying a gas under pressure tolift the mollusks to the boat towing the dredge. This apparatus has forthe most pair :proven unsatisfactory, due to the lack of control whichmay be exercised over the rate of flow if the contents traveling throughthe tube. It has been found that the flow rate through a tube isproportional to the pressure differential between the ambient pressureabout the tube entry and the gas supply to the tube used to lift themollusks. Accordingly, the absence of an adequatedegree of control overthis pressure differential will result either in an excessive amount ofpressure which will result in an exceedingly high rate of flow of thecontents or conversely an insufficient amount of pressure which will notprove strong enough to elevate the mollusks from the ocean floor. In theinstance of an excessive rate of flow, the mollusks frequently will bedamaged, and thus be rendered unfit for processing. Moreover, thesubject pressure differential is a rapidly fluctuating parameter becausethe numerous dips and ridges in the ocean floor over which the dredgepasses cause frequent changes in the ambient water pressure about thedredge.

Still another problem encountered in ocean bed harvesting is thefrequency in which foreign matter and undesirable objects areencountered and tend to clog the passage through the tube to the boat,thereby rendering the system inoperative and resulting in great wastageof time and effort to clear the tube and commence harvesting again.

SUMMARY OF THE INVENTION The present invention overcomes the heretoforeset forth problems encountered with apparatus used for harvestingmollusks, and has for its primary object the provision of an apparatuswhich will at all times control the rate of flow of the mollusks throughthe channel means to the boat by maintaining a constant pressuredifferential between the gas supply to the channel means and the ambientpressure about the dredge means. There fore, any change in the level ofthe ocean bed which will vary the ambient pressure about the dredgemeans will automatically be compensated for by the instant invention toinsure and maintain the constant pressure differential as aforesaid.Additionally, the invention contemplates a unique device for clearingany clog-up in the channel means which might occur due to the presenceof foreign matter or the like being encountered by the dredge means andinjected into the channel means.

Briefly stated, the present invention comprises a dredge means adaptedto gather the mollusks on the ocrean floor, a channel means forconveying the mollusks away from the dredge means, means for supplyinggas under pressure to the channel means to induce movement of themollusks therethrough, means for measuring the pressure differentialbetween the gas supply to the channel means and the ambient pressureabout the dredge means, and means operatively associated with the gassupply means and measuring means to control the supply of gas in orderto maintain a predetermined pressure differential.

BRIEF DESCRIPTION OF THE DRAWINGS The various features of the apparatusof this invention will become apparent from the following detaileddescription set forth in connection with the accompanying drawings whichrelate to the preferred embodiment of the present invention and aregiven by way of illustration.

FIG. 1 is a perspective view illustrating a towing vessel drawing themollusk harvesting apparatus of the present invention.

FIG. 2 is a side perspective view partially broken away to show thefeatures of the present invention.

FIG. 3 is a schematic illustration of the various parts utilized in themollusk harvesting apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, wherein isset forth the environment of the present invention, there is illustrateda towing vessel or ship .10 which drags therebeneath along the oceanfloor a dredge means 11. Tow line 12 is connected to the vessel anddredge means in such a manner that the latter remains in verticalalignment with the former throughout the towing and harvestingoperation. Interconnecting the dredge means with the towing vessel is alarge diameter tube or channel means 14 through which the mollusks andother matter gathered by the dredge means 11 are passed on board theship. The dredge means comprises a pair of runners 16 suitable forsliding along the ocean floor and onto which are mounted various bracingmeans, such as upright braces 18 and inclined braces 19. Horizontalbraces 20 are spaced above and parallel to the runners 16, as is bestseen in FIG. 2. Forwardly of the dredge means 1.1 is a blade 21 having aknife-like edge hingedly connected at point 22 and swingable between aninoperative position shown in phantom lines and an operative positionshown in phantom lines beneath the runners 16 for skimming the ocean bedand directing the flow of matter there encountered upwardly along theblade, as will be hereinafter more specifically set forth. The blade isillustrated between two positions in FIG. 2, the solid line positionindicating the operative position. Bolts 23 suitably secured to therunners 16 pass through the sides of the blade 21 and maintain it in theoperative position between runners 16. Washers or other spacing elementsv24 about the bolts are used to vary the depth of cut of the blade inthe ocean floor. Forwardly of the knife-like edge of the blade 21 andalso mounted on the dredge means 11 is a water jet assembly 25 includingoutwardly projecting jet portions 26 which are adapted to supply waterunder pressure to the ocean bed immediately adjacent the knife edge ofthe blade 21 for agitating the surface of the ocean bed to facilitateskimming by the blade. A pump 27 on board the vessel supplies waterunder pressure via the conduit 28 to the water jet assembly 25.

Rearwardly of the blade 21 on the dredge means 111 is a ramp 29 Whichmay partly comprise of a grating .or other foraminous material, as shownin FIG. 2, allows sand and undersized mollusks to sift therethrough anddirects the movement of the larger mollusks upwardly and rearwardly ofthe dredge means for passage to the vessel, as will be hereinafterexplained. The ramp is pivotally mounted at hinge 30 adjacent the pointof pivotal connection of the blade 21, as is best seen in FIG. 2, and iselevatable by means of a hydraulic assembly comprising a piston andcylinder arrangement 32, which is pivotally connected between ears 31and 68 mounted on horizontal brace 20 and the edge of the ramp 2-9. Aplurality of hydraulic rams may be used to swing the ramp upwardlyadjacent the suction means of the present invention depending on theweight of the material being collected by the blade. A source ofhydraulic fluid 33 communicates with the hydraulic ram 32 by way of theconduit 34, best seen in FIG. 3.

Focusing now on the means for elevating the material collected by thedredge to the vessel, and more particularly to the tube 14 of thepresent embodiment which is mounted on the rearwardly inclined brace 19of the dredge 11, there is illustrated a flange 15 suitably secured toplate 17, which in turn is secured to the dredge by means of braces 19and 20. The tube .14, as previously mentioned, is of a large diameter tofacilitate the passage of larger mollusks or the like collected and topermit a large volume of these mollusks to pass on board the vesselwithin a short space of time. A cylindrical portion 35 is affixed to theflange 15 in conventional manner and includes a mouth or opening in theflange adjacent the upper edge of the ramp 29. The rearward end ofportion 35 is received in the tube 14 and sealingly retained therein ina well-known manner. Concentric with portion 35 is a manifold 36 whichis communicable via a conduit 37 to a compressor '55 on board the shipand which receives a gas, as for example, air, under pressure therein.The manifold 36 communicates with the interior of the tube 14 throughangularly disposed apertures 39 which direct the flow of gas upwardlythrough the tube and away from the dredge means, thereby creating asphere or area of suction at the mouth of portion 35 adjacent the upperedge of the ramp 2.9. The pressure, the velocity and the buoyancy of thegas injected through the apertures 39 is sufiicient to lift or elevatethe mollusks collected on the ramp 29 upwardly and on board the vessel10. Upon movement onto the vessel the mollusks are received in aseparator where they are further handled and collected for processing ina manner known to the art and not a part of the instant invention. Theseparator includes a closure member or door 41 hingedly mounted thereinat a point adjacent the connection of the tube 14 to the separator andwhich is movable to a position to seal off the tube from the separatorby means of a piston-cylinder arrangement 42, the latter best seen inFIG. 3. The hydraulic source 33 communicates with cylinder 42 viaconduits 43 to actuate the cylinder and effect sealing off the tube fromthe separator for purposes hereinafter to be set forth.

The elevating or lifting of the contents through the tube 14 is effectedby main compressor 44 which supplies gas, in this case air, underpressure to the manifold 36 by way of conduit 37. The main compressor44, such as Model 600 manufactured by Jaeger, can supply air at 600 ft./min. at about 125 p.s.i. The air from. the main compressor is used toblow the clams up through tube 14 and to also unclog tube 14 at itsupper end by blowing air through line 45 into the tube .14, as will bedescribed. Connected through valve 47 in conduit 37 is an alternateconduit 45 which communicates with the interior of the tube 14 adjacentthe separator 40. A valve 46 is provided in conduit 45 near the inlet totube 14. As evident from FIG. 3, the conduit 37 is provided with a valve47, which may be turned to direct the flow of gas from the compressor 44to the alternate conduit 45. It should thus be apparent from theembodiment described, that in the event that clogging occasioned by thepresence of foreign matter collected in the tube 14 should occur, thatblowback may be eifected to clear the tube of this foreign matter bymoving closure 41 to the position to seal off passage of the contentsfrom the tube 14 to the separator 40, turning valve 47 to stop the flowof gas under pressure to the manifold 36 thus preventing further lift ofthe mollusks through the tube 14, and opening the valve 46 to direct thegas under pressure to the tube '14 at the point adjacent the separatorthus supplying a blow-back force in the tube 14 to induce the foreignmatter or clogging refuse to move back into the ocean from whence itcame. In operation, it has been found that the gas from compressor 44has proven ample to overcome any clogging which occurs in the tube 14.It should further be appreciated that a conduit to pump 27 might beprovided which supplies water under pressure to the tube 14 adjacent theseparator 40 so that a fluid media might be used in lieu of a gaseousmedia from the compressor 44 to unclog the tube. Consequently, aconsiderable saving in time and eX- pense is effected, since generally,any clogging of the tube connecting the dredge on board the ship,involves detaching same from the tube and cleaning the latter outmanually.

Air from the small compressor 55, which delivers about 1 ft. /min. offiltered air at about p.s.i., is fed into the constant flow regulator orbubbler 56 which expels air at a constant volume through line 59 at apoint adjacent the dredge in form of bubbles, as shown in FIG. 3.Compressor 55 is a small commercial unit which delivers clean air to theconstant flow regulator 56. A duplicate compressor 55' or the samecompressor 55, if desired, can deliver clean air to the pressure reducer49, as will be later described. The constant flow regulator 56, such asNo. 62 VA Model manufactured by Moore, consists of a valve with a pairof diaphragms which permit a constant stream of air or bubbles to traveldown a small line. 5-9, i.e., A1, to the dredge. Change in pressure inline 59 is due solely to changes in depth that the dredge is pulled.

The air in line 59 also communicates with one of the stainless steelbellows in the pressure transmitter 61. The other stainless steelbellows in the pressure transmitter 61 is connected into line 37 whichcarries air from the main compressor 44. Pressure transmitter 61, suchas the M-Line Differential Pressure Transmitter manufactured by Leedsand Northrop, includes a pair of stainless steel bellows, as alreadynoted. One bellows is pneumatically connected into line 59 to sense thechange in pressure in line 59 due to the change in depth at which thedredge is pulled; while the other bellows is pneumatically connectedinto line 37, which delivers great quantity of air at high pressure tothe manifold 36. Power for operating the pressure transmitter 61 issupplied by a power source 69', such as battery or generator. By meansof electrical contacts and a small amplifier, an electrical signal frompressure transmitter 61 is delivered to the deviation controller 64. Thevalue of this signal depends on the physical distention of the twobellows. The deviational controller 64 interprets the signal receivedfrom the pressure transmitter 6 1 and transmits another electricalsignal to electro-pneumatic controller 51 which either pneumaticallycloses or opens valve 48. The pneumatic power required to operate valve48 is supplied from compressor 55' through pressure reducer 49 by meansof lines 50, 52.

The deviation controller 64, such as M-Line Model C.A.T. IndicatingController manufactured by Leeds and Northrop, has dial control stationwith dial controls, adjustments and meters to indicate position of valve48, a pre-set differential pressure and deviation from the pre-setpressure. The deviation controller 64 is especially useful during manualoperation of the dredge. The operator would set the differentialpressure at about 6 to p.s.i. One meter would show to what extent valve48 need be open to deliver the required air while another meter wouldindicate the speed at which the valve is being actuated to meet thepre-set value. When the operation is automatic, the meters are of aminor interest only.

Electro-pneumatic controller 51, an example of which is Model 657 GRmanufactured by Fisher, receives an electrical signal from deviationcontroller 64 and pneumatically operates the valve 48 with air deliveredfrom compressor 55 through pressure reducer 49. The sole purpose ofpressure reducer 49' is to provide a small amount of clean air forpneumatic operation of valve 48. Model 67 FRTC, made by Fisher, is asuitable unit for purposes described herein.

When operating the apparatus described herein, one should know that eachfoot of depth in the ocean equals approximately /2 p.s.i. Therefore, ifthe dredge is pulled into a depression in the ocean floor of about 14-feet, the pressure of the air delivered to the clam hose manifold shouldbe increased by 7 p.s.i. to maintain proper operation of the air lift ofthe clams. The adjustment is automatically made in the following manner:When the dredge descends into the depression, pressure in line 59increases and expands one of the bellows in the pressure transmitter 61.Physical distention of the bellows changes the electrical signaldelivered to the deviation controller 64 which received the signal,analizes it and transmits another electrical signal to theelectro-pneumatic controller 51. The electrical signal received bycontroller 51 from the deviation controller 64 actuates pneumaticopening of valve 48 to compensate for the greater depth by allowing moreair under pressure to enter manifold 36. As valve 48 is opened, more airrushes through line 37 into manifold 36 and also more air enters theother bellows to partially off-set the physical distention of the firstbellows. These changes occur incrementally with the result that in ashort period of time, valve 48 would be opened sufficiently to balancethe system. It should be understood that if the dredge is pulled onto acrest of the ocean floor, then the system would compensate for thechange in depth by partially closing valve 48.

One additional feature of the dredging embodiment of the presentinvention is the apparatus which is used to apprise the operator of theposition of the ramp 29 during the dredging operation. Proximityswitches 66 and 67 are mounted on the side of the dredge means 11 at thetwo extreme positions of pivotal movement of the ramp 29 and arecontacted in these positions. Suitable signaling apparatus on board thevessel indicate the position of the ramp when the proximity switches arecontacted, so that in the event a heavy obstacle or other foreign matterrides up onto the ramp and moves near the mouth of the tube 14, the rampmay be swung down by actuating the hydraulic rams 32 to allow thematerial to pass off the ramp and behind the dredge. Moreover, theforeign matter blown back from the tube 14 during the blow-backoperation herein set forth will generally be removed from the dredgeonto which it is blown by actuating the ramp downwardly to the extremelower position to allow the material to pass out the rear of the dredgemeans 11.

Although one embodiment of the present invention has been hereinillustrated and described, it will be evident to those skilled in theart that various modifications may be incorporated into the details ofproduction without departing from the principles herein set forth.

What is claimed is:

1. Apparatus for harvesting mollusks or the like comprising dredge meansadapted to gather said mollusks on an uneven ocean bed, channel meansdefining an enclosed path of travel for said mollusks connected to saiddredge means, means for supplying gas under pressure to said channelmeans at a point adjacent said dredge means whereby the buoyancy andvelocity of said gas induce movement of said mollusks through saidchannel means, means for measuring the pressure differential between thegas supplied to said channel means and the ambient pressure of thedredge means, means operatively associated with said gas supply meansand said measuring means to control the supply of gas in order tomaintain a predetermined pressure differential whereby said molluskswill be moved at a controlled rate in the channel means irrespective ofthe ambient pressure.

2. Apparatus according to claim 1, wherein said dredge means includes ablade, a pivotally mounted ramp and motor means adapted to move saidramp.

3. Apparatus according to claim 1, including a receptacle adapted toreceive the mollusks conveyed through said channel means, said channelmeans being a flexible hose.

4. Apparatus according to claim 1, wherein said gas supply means incudesa manifold concentric with said channel means, said manifold havingapertures communicable with the interior of said channel means andangularly disposed therewith to direct the gas into the channel meansaway from the dredge means.

5. Apparatus according to claim 1, wherein said measuring means includesmeans for supplying gas at a predetermined rate of pressure to the areasurrounding said dredge means, and means interposed between said gassupply means to said channel means and said gas supply means to saiddredge means to sense and transmit the difference in pressure to saidcontrol means.

6. Apparatus according to claim 1, wherein said control means includes avalve associated with said gas supply means, means to adjust said 'valveto limit or increase the flow of gas, pressure differential maintainingmeans operatively associated with said adjustment means and responsiveto said measuring means whereby a constant pressure differential ismaintained.

References Cited UNITED STATES PATENTS 2,076,823 4/1937 Newell 37-623,153,290 10/1964 Saito 3762 3,248,812 5/1966 Gardner, Jr. 37613,521,386 7/1970 Francklyn 3755 ALDRICH F. MEDBERY, Primary Examiner

